Video editing using mobile terminal and remote computer

ABSTRACT

A method for video editing using a mobile terminal and a remote computer is disclosed. A user selects a user video to edit using a mobile application of the mobile terminal. The user selects a visual effect and parameters of the visual effect using the mobile application. Subsequently, the mobile application provides a preview of the visual effect superimposed over the user video using a series of still images representing the visual effect. When the user confirms the preview, the mobile terminal generates a request for video editing and sends the request to a server. The request includes identification of the visual effect for combining the visual effect and the user video as confirmed by the preview. Based on the request from the mobile terminal, the server combines a video clip of the visual effect and the user video into a resulting video.

BACKGROUND Field

The present disclosure relates to video editing. More specifically, thepresent disclosure relates to video editing using a mobile terminal andat least one remote computer.

Discussion of Related Technology

People use smartphones to take and edit videos. Simple video editinglike trimming can be done on smartphones. Smartphones may not haveprocessing power or functions of more complex video editing likesuperimposing visual objects. More complex editing is typicallyperformed using desktop computers or specialized systems.

SUMMARY

One aspect of the invention provides a method of video editing. Themethod comprises: providing a video editing mobile application on amobile terminal, wherein the video editing mobile application does nothave the capability of video editing to overlay a user selected visualeffect video clip over a user selected user video for generating asingle resulting video while the video editing mobile application offersvideo editing of adding the user selected visual effect video clip tothe user selected user video by computing power of one or more remotecomputers, wherein the video editing mobile application comprisesalpha-format still images corresponding to each of a plurality of visualeffects offered therein; receiving a user command for selecting a firstuser video for editing; receiving at least one user command for adding afirst one of the plurality of visual effects to the user selected firstuser video, wherein adding involves selecting the first visual effect,and selecting a first time window for adding the first visual effectwithin a time span of the first user video; providing a previewdisplaying a series of alpha-format still images over the first uservideo to emulate the first visual effect over the first user videowithout generating a single video clip in which the first visual effectoverlays the first user video; in response to a user's confirmation ofthe preview, uploading, to at least one remote computer, command datafor adding the first visual effect to the first user video at the firsttime window and at the at least one location such that the at least oneremote computer performs video editing of combining a first alpha-formatvideo clip for the first visual effect with the first user video inaccordance with the command data to generate, a single resulting videoin which the first alpha-format video clip for the first visual effectoverlays the first user video at the first time window and at the atleast one location; and receiving the single resulting video for playingon the mobile terminal, wherein each still image of the series ofalpha-format still images comprises a non-transparent visual effect witha transparent background, wherein the first alpha-format video clipcomprises a non-transparent visual effect with a transparent background.

In the above-described method, the command data identifies the firstuser video, identifies the first visual effect, specifies the first timewindow for adding the first visual effect within the time span of thefirst user video. Adding further involves selecting at least onelocation for adding the first visual effect within a display area of thefirst user video, wherein the command data further specifies the atleast one location for adding the first visual effect within the displayof the first user video. The series of alpha-format still imagescomprises a first alpha-format still image and a second alpha-formatstill image immediately following the first alpha-format still image,wherein in the preview the series of alpha-format still images aredisplayed in sequence such that at a first point in time of the preview,the first alpha-format still image is displayed alone and that at asecond point in time of the preview subsequent to the first point, thesecond alpha-format still image is displayed alone, wherein there is nooverlap of two or more alpha-formal still images at a given point intime of the preview. Still in the above-described method, the series ofalpha-format still images comprises a first alpha-format still image anda second alpha-format still image immediately following the firstalpha-format still image, wherein in the preview the series ofalpha-format still images are displayed in sequence such that at a firstpoint in time of the preview, the first alpha-format still image isdisplayed alone and that at a second point in time of the previewsubsequent to the first point, the first and second alpha-format stillimages are displayed together. At a third point in time of the previewsubsequent to the second point, the second alpha-format still image isdisplayed alone. At the second point, display strength of thenon-transparent visual effect of the first alpha-format still image islower than display strength of the non-transparent visual effect of thefirst alpha-format still image, displayed at the first point such thatthe non-transparent visual effect of the first alpha-format still imagefades out over time from the first point to the second point. The mobileapplication comprises a visual effect library storing the series ofalpha-format still images for the first visual effect, wherein thevisual effect library does not store or comprise an alpha-format videoclip for the first visual effect.

Another aspect of the invention provides a mobile terminal comprising atouch screen display, a memory and at least one processor, wherein themobile terminal comprises video editing mobile application softwarestored in the memory for executing using the at least one processor,wherein the video editing mobile application software does not have thecapability of video editing to overlay a user selected visual effectvideo clip over a user selected user video for generating a singleresulting video while offering video editing of adding the user selectedvisual effect video clip to the user selected user video by computingpower of one or more remote computers, the video editing mobileapplication comprising alpha-format still images corresponding to eachof a plurality of visual effects offered therein, the video editingmobile application software configured: to receive a user command forselecting a first user video for editing; to receive at least one usercommand for adding a first one of the plurality of visual effects to theuser selected first user video, wherein adding the first visual effectto the first user video involves selecting the first visual effect, andselecting a first time window for adding the first visual effect withina time span of the first user video; to provide a preview displaying aseries of alpha-format still images over the first user video to emulatethe first visual effect over the first user video without generating asingle video clip in which the first visual effect overlays the firstuser video; in response to a user's confirmation of the preview, toupload, to at least one remote computer, command data for adding thefirst visual effect to the first user video at the first time window andat the at least one location such that the at least one remote computerperforms video editing of combining a first alpha-format video clip forthe first visual effect with the first user video in accordance with thecommand data to generate a single resulting video in which the firstalpha-format video clip for the first visual effect overlays the firstuser video at the first time window and at the at least one location;and to receive the single resulting video for playing on the mobileterminal, wherein each still image of the series of alpha-format stillimages comprises a non-transparent visual effect with a transparentbackground, wherein the first alpha-format video clip comprises anon-transparent visual effect with a transparent background.

In the above-described mobile terminal, the command data identifies thefirst user video, identifies the first visual effect, specifies thefirst time window for adding the first visual effect within the timespan of the first user video, and specifies the at least one locationfor adding the first visual effect within the display of the first uservideo. Adding further involves selecting at least one location foradding the first visual effect within a display area of the first uservideo, wherein the command data further specifies the at least onelocation for adding the first visual effect within the display of thefirst user video. The series of alpha-format still images comprises afirst alpha-format still image and a second alpha-format still imageimmediately following the first alpha-format still image, wherein in thepreview of the series of alpha-format still images are displayed at aregular time interval in sequence such that at a first point in time ofthe preview, the first alpha-format still image is displayed alone andthat at a second point in time of the preview subsequent to the firstpoint, the second alpha-format still image is displayed alone, whereinthere is no overlap of two or more alpha-formal still images at a givenpoint in time of the preview.

Still in the above-described mobile terminal, the series of alpha-formatstill images comprises a first alpha-format still image and a secondalpha-format still image immediately following the first alpha-formatstill image, wherein in the preview of the series of alpha-format stillimages are displayed at a regular time interval in sequence such that ata first point in time of the preview, the first alpha-format still imageis displayed alone and that at a second point in time of the previewsubsequent to the first point, the first and second alpha-format stillimages are displayed together. At a third point in time of the previewsubsequent to the second point, the second alpha-format still image isdisplayed alone. At the second point, display strength of thenon-transparent visual effect of the first alpha-format still image islower than display strength of the non-transparent visual effect of thefirst alpha-format still image displayed at the first point such thatthe non-transparent visual effect of the first alpha-format still imagefades out over time from the first point to the second point. The mobileapplication comprises a visual effect library storing the series ofalpha-format still images for the first visual effect, wherein thevisual effect library does not store or comprise an alpha-format videoclip for the first visual effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a video editing system according to embodiments.

FIG. 2 illustrates a video editing preview on a mobile terminal andcorresponding video editing on a server according to embodiments.

FIG. 3 illustrates components of a video editing system according toembodiments.

FIG. 4 illustrates a visual effect library on a mobile terminal and acorresponding visual effect library on a server according toembodiments.

FIG. 5 illustrates superimposing visual effects over a user videoaccording to embodiments.

FIG. 6 illustrates a procedure of video editing according toembodiments.

FIG. 7A illustrates an interface of mobile application when a user videois selected according to embodiments.

FIG. 7B illustrates an interface of mobile application when a usernavigates a user video according to embodiments.

FIG. 7C illustrates an interface of mobile application when a userenters a command for adding a visual effect using according toembodiments.

FIG. 7D illustrates an interface of mobile application when a userenters a command for adding a visual effect using according toembodiments.

FIG. 7E illustrates an interface of mobile application when a visualeffect is selected to be added to a user video according to embodiments.

FIG. 8A illustrates an example timeline of displaying still images ofvisual effect according to embodiments.

FIG. 8B illustrates an example timeline of displaying still images ofvisual effect according to embodiments.

FIGS. 9A-9C illustrate setting locations of visual effect on a mobileapplication according to embodiments.

FIGS. 10A-10C illustrate a preview of visual effect changing itslocations according to embodiments.

The drawings are provided to illustrate examples and embodimentsdescribed herein and are not intended to limit the scope of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will now be described with reference to theaccompanying drawings. The terminology used in the description presentedherein is not intended to be interpreted in any limited or restrictivemanner, simply because it is being utilized in conjunction with adetailed description of certain specific embodiments of the invention.

Video Editing on Smartphone

With the improvement of computing power of smartphones, editing videoscan be performed on a smartphone. However, for better management ofsmartphone resources, and for more sophisticated video editing, it maybe desirable to delegate video editing tasks to a computer having moreresources and more video editing functionalities. The present inventionprovides a video editing system and method that utilize at least onemobile terminal for user interface and at least one remote computer forediting user videos.

User Instructions on Mobile Terminal and Video Editing on Server

Referring to FIG. 1, a mobile terminal 100 is connected to a server 200wired or wireless via the Internet or information network 300. Themobile terminal 100 includes a mobile application for video editing. Theserver 200 includes software for editing user videos. In embodiments, auser enters video editing instructions to the mobile application. Themobile application of the mobile terminal 100 presents a preview for theuser's review and confirmation. In response to the user's confirmationfor editing, the mobile application of the mobile terminal 100 sends avideo editing request to the server 200. In response to the videoediting request, the server 200 performs editing of the user video andgenerates a resulting edited video.

As illustrated in FIG. 2, in embodiments, the resulting video 210generated by the server 200 corresponds to the preview 110 presented onthe mobile terminal 100 in a manner in which for each visual effectincluded in the preview 110, the resulting video 210 includes acorresponding visual effect. The resulting video 210 is a single videoclip superimposing the user video and at least one visual effect. On theother hand, the corresponding preview is not a single video clip andrather a visual representation of the user video along with still imagesthat correspond to the at least one visual effect. In embodiments, topresent the preview of video editing, the mobile terminal 100 storesstill images of visual effects. On the other hand, the server 200 storesvideo clips that correspond to the still images stored in the mobileterminal's library.

Video Editing System

FIG. 3 illustrates components of the mobile terminal 100 and the server200 of a video editing system according to embodiments. The mobileterminal 100 includes a mobile application 120, a visual effect library140 and a user video storage 160. The server 200 includes video editingsoftware 220 and a visual effect library 240.

Mobile Terminal

In this disclosure, the term “mobile terminal” refers to mobile consumerelectronic devices, such as smartphones, tablet computers, laptopcomputers, wearable computing devices, and other mobile computingdevices. In embodiments, the mobile terminal includes a display, a userinput device, a memory and at least one processor for executingsoftware. In some embodiments, the mobile terminal includes a touchscreen display although not limited thereto.

Server

In this disclosure, the term “server” refers to one or more computersthat are typically stationary rather than mobile, although not limitedthereto. In some embodiments, the server is at least one networkedcomputer of a service provider for providing video editing services.

Mobile Application

The mobile application 120 is software installed on mobile terminal 100and capable of accessing components of mobile terminal 100 for providinguser interfaces for video editing. The mobile application 120communicates with the video editing software 220 of the server 200 fordelegating a video editing task to the server 200. The mobileapplication 120 provides user interfaces for receiving user commands forvideo editing, providing a video editing preview, and playing an editedor resulting video from the server 200.

Visual Effect Library of Mobile Application

The visual effect library 140 is data store of visual effects for use inthe mobile application 120. In embodiments, the visual effect library140 stores a plurality of sets of still images, in which each set ofstill images represents one visual effect. As illustrated in FIG. 4, thevisual effect library 140 further stores information and data relatingto the visual effects (A, BB, . . . AZ). For each visual effect, inembodiments, the visual effect library 140 stores an identification(ID), an accompanying sound recording, the number of still images (imagecount), etc. In other embodiments, the visual effect library 140includes addresses or locations of the still images for each visualeffect.

Visual Effects

In the present disclosure, the term “visual effect” or “visual effects”refer to one or more visual objects for adding to a user video. Thevisual object may be stationary or moving on a screen. The visual objectmay be colored and translucent, but not a filter to apply to a fullscreen of frames of the user video. When added to the user video, avisual effect may accompany with a sound recording.

Still Images for Visual Effects

A set of still images for each visual effect are snapshots or frames ofa corresponding visual effect video. In embodiments, each still imageincludes one or more non-transparent objects or portions on atransparent background, referred to as an alpha (α) format still image.The still images of a visual effect are to be overlaid over user videoframes on the mobile application 120 in a preview without forming anintegrated video.

User Video Storage

The user video storage 160 is data store for user videos. Inembodiments, the user videos stored in the user video storage 160include videos captured at the mobile terminal 100 and/or videosdownloaded from other sources.

Video Editing Software of Server

The video editing software 220 is software of the server 200 forperforming video editing tasks based on a request from the mobileapplication 120. Video editing by the video editing software 220 is,among others, combining a user video and at least one visual effectvideo such that the resulting video is in a single file and the visualeffect video overlaps some frames of the user video.

Visual Effect Library of Server

The visual effect library 240 is server-side data store of visualeffects. In embodiments, the visual effects library 240 of the server200 stores video clips for visual effects (A, BB, . . . , AZ), e.g., onevideo clip for a visual effect. As illustrated in FIG. 4, the visualeffect library 240 further stores information and data relating to thevisual effects such as an identification (ID), a frame rate of the videoclip (frame per second, fps), an accompanying sound recording, etc.

Video Clips for Visual Effects

Each video clip for a visual effect includes a transparent backgroundand one or more non-transparent objects or portions, referred to as analpha (α) format video clip. The frames of the video clip are to beintegrated with user video frames to form a single edited video by videoediting. In embodiment, alpha (α) format that supports an alpha (α)channel for storing transparency information of each pixel is used forthe visual effect video clip.

Visual Effects in Visual Effect Libraries of Mobile Terminal and Server

Referring to FIG. 4, in embodiments, each visual effect has still imagedata in the mobile terminal 100 and video data in the server 200. Withregard to the visual effect A, for example, a series of still images(A₁-A₁₀) are stored in the visual effect library 140 of the mobileterminal 100, and a video clip (A) is stored in the visual effectlibrary 240.

Relationship Between Video Clip and Still Images

For each visual effect, the video clip stored in the server 200 directlycorresponds to the still images stored in the mobile terminal. In someembodiments, the still images A₁-A₁₀ are a subset of frames selectedfrom the corresponding video of visual effect A. In some embodiments,each still image is a snapshot or frame of the video clip or a modifiedor simplified version of the snapshot or frame. In embodiments, for eachvisual effect, the number of still images (image frame count) issubstantially less than the number of frames in the corresponding video(video frame count). For example, the video frame count is 5, 10, 20,30, 40, 50, 60, 70, 80, 90, 100 and 200 times greater than the imageframe count for the visual effect. In embodiments, the ratio of thevideo frame count to the image frame count is in a range formed by anytwo numbers listed in the previous sentence.

Example Video Editing

FIG. 5 illustrates an example timeline of video editing according toembodiments, in which a user video for editing runs from to through t₆.In the illustrated example, the visual effect A 520 is superimposed overthe user video 510 from t₁ to t₃, and the visual effect B 530 issuperimposed over the user video 510 from t₂ to t₅. In the example,between t₂ and t₃, both visual effect A and visual effect B aresuperimposed with the user video 510.

Example Video Editing Procedure

FIG. 6 illustrates an example procedure of video editing. First, a useractivates the mobile application 120 on the mobile terminal 100. Then,at 610, the user selects a user video 510. Subsequently, at 620 the userselects a visual effect and at 630 selects parameters for adding thevisual effect to the selected user video. In embodiments, the user mayadd more than one visual effect as in FIG. 5. Subsequently, at 640 themobile application 120 plays a preview for the user's review andconfirmation of adding the visual effects. In response to confirmation,at 650, the mobile application generates a video editing request forsending to the server 200 at 660. In response to the video editingrequest, at 670 the server 200 edits the user video in accordance withthe request. Subsequently, at 680 completion of the video editing isnotified to the mobile application 120, and at 690 the user may play theedited video on the mobile application 120

Selecting User Video

At 610 the user selects a user video from user videos stored in the uservideo storage 160. In response, the mobile application 120 displays ascene of the user video 510 and provides a user interface for navigatinga timeline of the selected user video 510. In the alternative toselecting one from the user video storage 160, the user may select avideo for editing from the Internet or a network. Then, the mobileapplication 120 may download the selected user video or part of theselected video for displaying on its user interface.

Selecting Visual Effect and Setting Parameters

At 620, the user selects one or more visual effects to add to the uservideo. In embodiments, the mobile application 120 provides a userinterface for selecting a visual effect from the visual effectsavailable in the visual effect library of the mobile terminal 100.Subsequent to selection of each visual effect, e.g. visual effect A, at630, the user sets one or more parameters for the selected visual effectA via the user interface of the mobile application 120. In embodiments,the parameters include time frame (start-end), size, orientation,location within the screen, and display strengths (degree oftransparency) of the visual effect A. As the user selects visual effectsand their parameters, the mobile application 120 saves the userselections and settings.

Preview

Subsequently, at 640, a preview of video editing may be displayed at theuser's request. In embodiments, the preview is a play of the selecteduser video along with the still images of the selected visual effectsthat are superimposed over the user video frames in accordance with theuser's setting of the parameters. In embodiments, the preview is not anintegrated video, in which the still images are incorporated orintegrated with the user video. In other embodiments, at least part ofthe still images may be integrated with or incorporated into the uservideo to provide the preview. The user may approve the preview or goesback to steps 620 and 630 for changes.

Request for Video Editing

Subsequently at 650, the mobile application 120 generates and sends avideo editing request to the server 200 at the user's command. The videoediting request includes details of the user's selections and settingsfor video editing. In embodiments, the video editing request includesthe selected user video, identification of selected visual effect andparameters for each visual effect. In some embodiments, the videoediting request includes identification or location information of theuser video rather than including the user video data itself.

Video Editing at Server

At 670, the video editing software 220 of the server 200 performs videoediting in accordance with the video editing request from the mobileapplication 120. The video editing software 220 retrieves the selecteduser video if needed. Also, the video editing software 220 retrieves thevideo clip for each visual effect identified in the video editingrequest. Then, the video editing at the server 200 relates to combiningthe video clip of the selected visual effect with the selected uservideo as specified by the parameters included in the request from themobile application 120.

Combining Videos to Add Visual Effects

During video editing, the video editing software 220 superimposes framesof the video clip of the selected visual effect over frames of the uservideo based on the timeframe specified in the video request.Specifically, in the video editing, a frame of the visual effect videoclip and a frame of the user video are integrated as a single frame suchthat the video editing results in a single integrated videoincorporating visual effect from the video clip in the user video. To dothe frame-by-frame integration, in some embodiments, the video editingsoftware 220 may determine if the frame rates of the user video andvisual effect video clip and adjust the frame rate of the visual effectvideo clip to match the frame rate of the user video.

Example Mobile Application Interfaces

FIGS. 7A-7E illustrate example user interfaces of the mobile application120 for video editing. Referring to FIG. 7A, a first window 810 of themobile application 120 displays the starting frame (t₀) of the uservideo 510. A second window 820 of the mobile application 120 displays avideo time-bar 822 showing frames of the user video 510. In the secondwindow 820, the mobile application 120 provides an indicator 824indicating position of the current frame (scene) displayed in the firstwindow 810 on the video time-bar 822. The mobile application 120graphical provides icons 830 representing video editing available in themobile application. Each of the icons 830 represents color adjusting,adding background music, overlaying visual effects, and trimming. InFIG. 7B, the mobile application 120 displays the first scene (t₁) of theuser video 510 as the user moves the video time-bar 822.

FIG. 7C-7E illustrates interface of the mobile application 120 when theuser selects the visual effect A and selecting parameters of the visualeffect A at the steps of 620 and 630. In FIG. 7C, the mobile application120 displays multiple icons 840 showing visual effect categoriesavailable when the user selects an icon 831 of overlaying visual effectsamong the icons 830. In FIG. 7D, the mobile application 120 displaysmultiple icons 843 representing visual effects in the selected categorywhen the user selects an icon 842 representing heart-shape visualeffects.

When the user selects the icon 844 (representing the Visual Effect A520) the mobile application 120 displays a con 860 indicating locationand size of the visual effect A in the first window 810 over a scene ofthe user video 510. The mobile application 120 displays a time line 850for indicating start/end of the visual effect A. The timeline 850 issized and aligned with the video time-bar 822 for indicating acorresponding portion of the user video 510 where the visual effect Awill be combined. In embodiments, the mobile application 120 providesthe icon of the Visual Effect A using at least one form the still imagesA₁-A₁₀. In embodiments, the user can set a starting point of the visualeffect by moving the time line 850 relative to the time bar 822 of theuser video. In some embodiments, the user can adjust size of the visualeffect A by dragging a size-adjusting mark 862 provided along with theicon 860. When the user selects the confirm icon 870 the mobileapplication 120 provides a preview of the visual effect A over the uservideo 510.

Presentation of Visual Effect in Preview

FIG. 8A illustrates an example timeline of displaying still images of avisual effect A (FIG. 5) in a preview. The visual effect A begins at t₁and continues until t₃ (t₁+5 second). In the illustrated example of FIG.8A, each still image stays for 0.5 sec. in the preview such that eachstill image is presented along with multiple frames of the user video510. Specifically, in the first time segment from t₁ to t₁+0.5, thefirst still image A₀₁ is displayed over the frames of the user video 510in the same time segment. For the following segment, from t₁+0.5 tot₁+1.0, the second still image till image A₀₂ is displayed over theframes of the user video 510 in the same time segment. In otherembodiments, based on user settings and/or input, the time segment foreach still image may change.

Showing Still Images in Preview

In some embodiments, the mobile application 120 displays the stillimages A₁-A₁₀ one after another in sequence without overlapping witheach other as in FIG. 8A. In other embodiments, as in FIG. 8B, two ormore still images may be displayed at a given time during preview. Insome embodiments, the transparency (display strength) of the object(s)included in each still image is constant and does not change over timeduring the time segment in which the particular still image is presentedin the preview. In other embodiments, the transparency (displaystrength) of the object(s) included in each still image changes overtime during the time segment in which the particular still image ispresented in the preview.

On-Off Display Strength (Transparency) of Objects in Still Image

In the example of FIG. 8A, each of the still images A₀₁-A₁₀ is displayedat either of 100% displays strength and 0% displays strength duringdisplay of the visual effect A in preview. For example, still image A₀₁is at 100% during the first time segment and at 0% for the rest of timesegments. Display strength of 100% is 0% transparency, which is todisplay the object(s) of each still image as original. Display strengthof 0% corresponds 100% transparency, which will result in no display ofthe object(s) of visual effect. In embodiment, alpha (α) format thatsupports an alpha (α) channel for storing transparency information ofeach pixel of the still images are used for changing displays strength.

Staggering Display Strength and Overlapping Display of Still Images

In the example of FIG. 8B, the still image A₀₉ is displayed in the timesegment between t₁+4.0 and t₁+5.0. The display strength of the stillimage A₀₉ gradually increases (fade-in) to its peak at t₁+4.5 and thengradually decreases (fade-out) until t₁+5.0. From t₁+4.0 to t₁+4.5, thestill image A₀₉ is displayed together with the still image A₀₈ as thestill image A₀₈ fades out. Similarly, from t₁+4.5 to t₁+5.0, the stillimage A₀₉ is displayed together with the still image A₁₀ as the stillimage A₁₀ fades in. In the illustrated example, while ending of stillimage A₀₈ an beginning of still image A₁₀ coincide at the time t₁+4.5,in other embodiments, beginning of still image A₁₀ may be delayed suchthat there is some time period in which only the still image A₀₉ isdisplayed as visual effect along with the user video frames. Also, inother embodiments, the still image A₁₀ may begin before completedisappearance of the still image A₀₈. The overlapping display andstaggering display strength individually and in combination areadvantageous as the display of these still images can generate smoothermotions with a smaller number or count of still images than the on-offdisplay strength as illustrated in FIG. 8A.

Visual Effect Changing Locations

FIGS. 9A to 9C illustrates setting different locations of the visualeffect A at multiple points of the timeline of user video. FIGS. 10A to10C illustrates a preview of the visual effect A changing its locationsalong the timeline of the user video. Referring to FIGS. 9A to 9C,visual effect icons 962, 964, 966 represent a visual representation ofthe visual effect A at corresponding points 952, 954, 956 in thetimeline 850. The user can adjust location of the visual effect A at thepoint 952 by moving the moving visual effect icons 962 as in FIG. 9A.Similarly, the user can change locations of the visual effect A at thepoints 954, 956 in the timeline 850 by moving the icons 964, 966. Foreach of the points 952, 954, 956 the mobile application 120 stores thelocation of the visual effect as part of meters for video editing. Themobile application 120 includes the stored locations in a request forserver-side video editing. Based on the request, the server 200generates a resulting video in which the visual effect A moves along atrace connecting the multiple locations of 962, 964, 966. In someembodiment, parameters of the visual effect A for overlaying includedifferent settings of the visual effect A at two or more points in thetimeline of the visual effect A.

Mobile Application—Not performing Video Editing by Itself

In embodiments, mobile application 120 does not perform, by itself, avideo editing to combine visual effects to user videos because suchvideo editing task is too heavy for limited computational power of themobile terminal 100. Instead, the mobile application 120 provide of avideo editing and delegates the video editing to the server 200 to takeadvantage of computational power of the server 200. In embodiments, apreview of visual effects is provided using-still-images representingthe visual effects without using a video clip of the visual effects.Process of providing a video editing preview is not a simplified versionof corresponding video editing at the server because the mobileapplication 120 does not modify the user video or create a new videofile incorporating the visual effects to the user video.

Modifications, Combinations and Sub-Combinations

Although the invention has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that various features and aspects of the present invention extendbeyond the specifically disclosed embodiments to other alternativeembodiments. In addition, while a number of variations have been shownand described in detail, other modifications, which are within the scopeof the invention, will be readily apparent to those of skill in the artbased upon this disclosure. It is also contemplated that variouscombinations or sub-combinations of the specific features and aspects ofthe embodiments may be made and still fall within the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed invention. Thus,it is intended that the scope of the present invention herein disclosedshould not be limited by the particular disclosed embodiments describedabove, and that various changes in form and details may be made withoutdeparting from the spirit and scope of the present disclosure as setforth in the following claims.

What is claimed is:
 1. A computer-readable memory storing mobileapplication software wherein, when executed in a smartphone, the mobileapplication software is configured to perform a method comprising:receiving, on the smartphone, a user command for selecting a user videofor editing; receiving, on the smartphone, at least one user command foradding a first visual effect among a plurality of predetermined visualeffects to the selected user video, wherein adding involves selectingthe first visual effect, selecting a first time window for adding thefirst visual effect within a time span of the selected user video;subsequently displaying, on the smartphone, a preview emulating anedited version of the selected user video without generating a videoclip of the edited version locally in the smartphone such that, indisplaying the preview, a first series of alpha-format still imagescorresponding to the first visual effect is superimposed over theselected user video according to the at least one user command withoutperforming frame-by-frame integration of the selected user video and thefirst series of alpha-format still images; in response to a user'sconfirmation of the preview, transmitting by the smartphone to at leastone remote computer, command data for generating the edited version inthe at least one remote computer such that a first alpha-format videocorresponding to the first visual effect is superimposed over theselected user video to provide the first visual effect in the first timewindow; and receiving, on the smartphone, the edited version from the atleast one remote computer, wherein each still image of the first seriesof alpha-format still images comprises a non-transparent presentation ofthe first visual effect with a transparent background, wherein the firstalpha-format video comprises a non-transparent presentation of the firstvisual effect with a transparent background, wherein the number offrames of the first alpha-format video during the first time window isgreater than the number of still images of the first series ofalpha-format still images during the first time window.
 2. Thecomputer-readable memory of claim 1, wherein the command data identifiesthe selected user video, identifies the first visual effect, specifiesthe first time window for adding the first visual effect within the timespan of the selected user video, and specifies at least one location foradding the first visual effect within the presentation of the selecteduser video.
 3. The computer-readable memory of claim 1, wherein thefirst series of alpha-format still images comprises a first alpha-formatstill image and a second alpha-format still image immediately followingthe first alpha-format still image, wherein at a first point of thepreview, the first alpha-format still image is displayed alone, whereinat a second point of the preview following the first point, the firstand second alpha-format still images are displayed together.
 4. Thecomputer-readable memory of claim 3, wherein at a third point of thepreview following the second point, the second alpha-format still imageis displayed alone.
 5. The computer-readable memory of claim 3, whereinat the second point of the preview, display strength of the firstalpha-format still image is lower than display strength of the firstalpha-format still image displayed at the first point of the previewsuch that the first alpha-format still image fades out over time fromthe first point to the second point.
 6. The computer-readable memory ofclaim 3, wherein at a third point of the preview following the secondpoint, the second alpha-format still image has a display strengthgreater than that of the second alpha-format still image at the secondpoint of the preview such that the second alpha-format still image fadesin over time from the second point to the third point.
 7. Thecomputer-readable memory of claim 1, wherein in displaying the preview,individual still images in the first series of alpha-format still imagesare displayed at a regular time interval in sequence.
 8. Thecomputer-readable memory of claim 1, wherein during the preview, eachstill image of the first series of alpha-format still images ispresented with multiple frames of the selected user video.
 9. Thecomputer-readable memory of claim 1, wherein the command data from thesmartphone comprises an identification of the first series ofalpha-format still images, wherein the at least one remote computeridentifies the first alpha-format video using the identification of thefirst series of alpha-format still images.
 10. The computer-readablememory of claim 1, wherein each of the first series of alpha-formatstill images is stored locally on the smartphone, and wherein each ofthe first series of alpha-format still images is associated with anidentification of the first visual effect.
 11. The computer-readablememory of claim 1, wherein the mobile application software does not havecapability of video editing to combine the first alpha-format video ofthe first visual effect and the selected user video into a single videoclip while being capable of causing the smartphone to display thepreview using the first series of alpha-format still images.
 12. Thecomputer-readable memory of claim 11, wherein when executed in thesmartphone, the mobile application software is configured to cause thesmartphone to present the preview using a first visual effect librarystored locally on the smartphone, the first visual effect librarycomprising the first series of alpha-format still images.
 13. Thecomputer-readable memory of claim 1, wherein to generate the editedversion, the at least one remote computer performs frame-by-frameintegration of the first alpha-format video and the selected user video.14. The computer-readable memory of claim 13, wherein the at least oneremote computer adjusts a frame rate of the first alpha-format video tomatch the frame rate of the selected user video.
 15. Thecomputer-readable memory of claim 1, wherein to generate the editedversion, the at least one remote computer combines the firstalpha-format video of the first visual effect and the selected uservideo to generate the edited version in a single video clip inaccordance with the command data from the smartphone.
 16. Thecomputer-readable memory of claim 15, wherein the command data from thesmartphone comprises an identification of the first series ofalpha-format still images, wherein the at least one remote computeridentifies the first alpha-format video using the identification of thefirst series of alpha-format still images.
 17. The computer-readablememory of claim 15, wherein the at least one remote computer generatesthe edited version using a second visual effect library stored locallyon the at least one remote computer, the second visual effect librarycomprising the first alpha-format video of the first visual effect,wherein the first alpha-format video is associated with anidentification of the first visual effect.
 18. The computer-readablememory of claim 17, wherein the command data from the smartphonecomprises an identification of the first series of alpha-format stillimages, wherein the at least one remote computer identifies the firstalpha-format video from the second visual effect library using theidentification of the first series of alpha-format still images.
 19. Thecomputer-readable memory of claim 18, wherein to generate the editedversion, the at least one remote computer performs frame-by-frameintegration of the first alpha-format video and the selected user video.20. The computer-readable memory of claim 19, wherein the at least oneremote computer adjusts a frame rate of the first alpha-format video tomatch the frame rate of the selected user video.